Soil Microbial Community Diversity and Its Relationships with Geochemical Elements under different Farmlands in Shouguang,China

The aims of this study were to investigate soil microbial community characteristics and their interrelationships with soil geochemistry under different farmlands in Shouguang, China. The traditional dilution plate counts, BIOLOG system, and fatty acid methyl ester (FAME) analyses were used to assess microbial populations, substrate utilization, and fatty acid profiles. The number of aerobic heterotrophic bacteria varied significantly among untilled land, maize, and mungbean fields. The amounts of actinomycetes, fungal fatty acids, and Gram-positive/Gram-negative bacteria ratios varied greatly among celery, tomato, and aubergine fields. In the tomato field, the soil microbial community characteristics were significantly different from other fields. Principal component analysis of BIOLOG and FAME data revealed differences in the catabolic capability and fatty acid profiles of soil microbial communities among different farmlands. Spearman correlation analyses showed that in these sand clay soils of Shouguang, microbial communities in different farmlands were closely correlated with soil geochemical elements, moisture, and organic matter.     

近7.0-0.73MaBP期间甘肃临夏盆地古气候演变的沉积物地球化学记录

位于青藏高原东北边缘临夏盆地新生代沉积蕴含了丰富的有关青藏高原隆升和环境演变信息。近７．０－０．７３ＭａＢＰ期间沉积物地化元素含量波动特征表明,具相同或相近表生地化性质的元素含量波动呈现大致相同的特征。由常量元素氧化物所揭示的此期间临夏盆地温湿变化明显地可以分成几个阶段,即７．０－５．３５ＭａＢＰ,虽有冷干与暖湿波动,但总体上却呈现出一种较为和缓、稳定的气候特征;至５．３５ＭａＢＰ前后,出现一具全球意义的冷峰,随后气候进入冷干与暖湿频繁、大幅剧烈波动的时期,可能同青藏高原此时开始的整体隆升并导致亚洲季风开始建立但极不稳定的状况有关。而３．４Ｍａ和２．９０Ｍａ两次强烈的构造运动的发生很可能使得青藏高原隆升至一个关键高度,此时亚洲季风已稳定建立,地化元素波动平缓,气候环境以冷湿为主要特征,湖相沉积发育。之后,１．６０Ｍａ前后高原再度隆升,导致黄河朔源侵蚀加剧,最终切穿临夏盆地,排干湖水,且此时高原巨大的山体已成为南来湿润气流的障碍,使内陆地区趋于干旱,温带荒漠开始发育,并在其四周广泛地开始了风成黄土的堆积,而黄土堆积中黄土与古土壤的交替出现仍是冷干与暖湿气候特征的反映。因此,近７．０－０．７３ＭａＢＰ期间临夏盆?     

三峡库区小江流域消落带土壤Zn各形态有效性及缓变型地球化学灾害分析

通过分析三峡库区小江流域消落带土壤Zn全量、形态及有效性,并基于缓变型地球化学灾害数学模型,研究了区域内土壤Zn的缓变型地球化学灾害特征。结果表明:研究区域内全量Zn的平均值为123.88 mg/kg,高于国家土壤环境质量一级标准,但明显低于二级标准。Zn的酸溶态、可还原态、可氧化态、残渣态平均值占全量平均值的百分比分别为2.93%、4.42%、8.71%和83.94%,有效态占4.51%。酸溶态、可还原态、可氧化态与有效态相关性密切;可还原态和可氧化态含量对有效态含量贡献较大。在小江流域消落带的土壤中Zn具有缓变型地球化学灾害特征,土壤中Zn有可释放总量向次生相态释放转化的趋势,其缓变型地球化学灾害临界值为130.67 mg/kg,32%的土壤样品具有爆发Zn缓变型地球化学灾害的可能性。     

拉拉铜矿集中开采区土壤地球化学基线值研究

确定土壤地球化学基线值对矿山地质环境影响评价意义重大,选择恰当的基线值计算方法对基于矿集区尺度精细评价尤为关键。本研究以拉拉铜矿集中开采区表层土壤地球化学数据为基础,采用统计学法和标准化法分别计算不同地质单元分区内土壤中As、Co、Cr、Cu、Fe、Hg、Mo、Ni、Pb、Zn的地球化学基线值,并与区内相关研究成果进行对比分析。结果表明:研究区土壤地球化学空间分布呈显著的分带性,在Pt区和TJK区分别计算各分区基线值比笼统计算区域性单一基线值更有实际意义;在矿集区内采用标准化法计算的土壤基线值略大于统计学法计算的基线值;在人类活动扰动小的TJK区内两种计算方法均适用,在人类活动扰动相对较大的Pt区内采用统计学法较标准化法更为适用。     

重庆紫色母岩及土壤As、Hg环境地球化学基线研究

为了掌握紫色土类中As和Hg在不同发育阶段土壤中元素含量的理论值(基线值),在重庆市合川区系统采集侏罗系沙溪庙组(J2s)紫色母岩及其不同发育程度的各土种样品,利用土壤"钛值"法测定和验证土壤发育程度;通过对土壤全量As、Hg的测定,采用标准化方法,建立紫色土类中灰棕紫泥土属As、Hg的环境地球化学基线模型。结果表明:侏罗系沙溪庙组(J2s)紫色母岩发育的土壤As、Hg的环境地球化学基线均表现为随土壤发育加深而轻度累积,As基线值大小顺序为母岩石骨子土半沙半泥土大眼泥紫黄泥,而Hg的基线值大小顺序为母岩石骨子土半沙半泥土紫黄泥大眼泥;Hg在土壤发育过程中的富集程度约大于As;深度发育土中As和Hg的化学基线值分别为5.94 mg kg-1、29.0μg kg-1,可作为重庆地区中性紫色土亚类、灰棕紫泥土属土壤污染评价的参考。     

合肥地区土壤Cu元素缓变型地球化学灾害研究

土壤元素的缓变型地球化学灾害具有重要危害。基于缓变型地球化学灾害数学模型,分别研究了合肥大兴镇地区和义城镇地区土壤中Cu元素的缓变型地球化学灾害特征并进行了对比。研究结果显示,大兴镇地区土壤中Cu元素有污染物可释放总量TRCPCu→污染物有效量CuE+C释放转化的趋势,其缓变型地球化学灾害模型为y=0.005 6x3-0.436 1x2+11.28x-90.803,约38%面积的土壤具有爆发Cu缓变型地球化学灾害的可能性,这与大兴镇是合肥的工业重镇有关。而义城镇地区土壤中Cu元素还不具有爆发缓变型地球化学灾害的可能性,这与该区以农业和养殖业为主有关。同时,土壤元素缓变型地球化学灾害的研究对土壤重金属污染预警具有重要的意义。     

Control of geochemical mobility of arsenic by liming in materials subjected to acid mine drainage

Background  Acid mine drainage (AMD) results from the exposure of sulfide materials to atmospheric water and oxygen. In addition to AMD, oxidation of arsenopyrite and other As-bearing sulfides can release arsenic (As) into the environment. In view of the risk to living organisms due to contamination of ground and surface water sources with As, this work was carried out to evaluate the effectiveness of lime (CaCO₃) in controlling the dispersion of this metalloid in the environment. Methods  Partially oxidized samples of sulfide bearing materials from gold mines in Brazil were used to evaluate the arsenic mobilization by leaching tests. Columns containing ground samples, with and without liming treatments, were leached with distilled water every two weeks over a 156-day period. Results and Discussion  The acid-base accounting (ABA) static tests classified the samples as potential acid forming materials. In the treatments without liming, As, Fe and S concentrations in the leachates were higher than after treatment with carbonate. Nevertheless, the effectiveness of liming and As mobilization were lower in the sample containing goethite. A high correlation between Fe and As concentrations in the leachates (r=0.749) suggests that iron (hydr)oxides retained arsenic in the solid phase. Oxidation rates of As bearing sulfides were increased at low pH (2.0–3.9), probably due to the enhanced activity of bacteria (Acidithiobacillus) and decreased rate of Fe precipitation, thus reinforcing generation of acid water, and consequently releasing As. Conclusions and Perspectives  Our results corroborate the use of lime to control the dispersion of As in AMD-affected environments. However, the effectiveness of the liming treatment seems to be dependent on the presence of iron (hydr)oxides in the sample. These findings can be useful to remediate areas affected by acid mine drainage and arsenic mobilization in partially oxidized sulfide materials. ESS-Submission Editor: Chengrong Chen, PhD (c.chen@griffith.edu.au)     

草河口地区沉积物和土壤中铊的地球化学行为

通过对草河口地区二道坊河沉积物和土壤中铊的分析与研究表明,该区域土壤中铊的含量高于世界与中国土壤铊含量的值;铊的富集特征具有一定的特殊性,并且铊在土壤和沉积物中与其相应性质关系有较大差异;在该河流沉积物的条件下,游离氧化锰对铊富集起着重要作用。     

海南岛东北部地区土壤农业地球化学评价

土壤的大量营养元素、微量元素分析结果表明,海南（琼）东北部地区土壤农业环境质量好,达到国家一级标准,是热带优质作物的理想生产基地.相对来说,母质为基性火山岩的土壤农业地球化学质量最好,水稻土壤次之,母质为花岗岩和砂页岩土壤较好,母质为浅海沉积物的土壤较差,冲积土壤最差.     

土壤地球化学特征影响下的土地利用规划研究——以信丰县为例

土地利用规划是在一定地球化学特征下开展和实施的,应重视地球化学调查评估成果在土地利用规划中的应用,综合考虑地球化学特征对土地利用规划编制和实施过程中的影响,提高规划的科学合理性.该研究探索了土壤地球化学调查评估成果在土地利用规划中的应用,体现了其必要性和可行性.并以信丰县为例,简析该区地球化学特征背景因素,提出将土壤地球化学特征运用于土地利用规划的思路,有助于完善土地利用规划的科学性和合理性.